How often do you see a riding lesson where the instructor shouts,at the rider whos horse has rushed off on the forehand, Half halt!. If we don t understand the timing,the reason why and how to execute a half halt this is completely useless. Often you will see the rider pull the outside rein and lean back,sending mixed messages to the horse,the rein will be restricting but the seat,where the rider has leant back will often be pushing the horse forwards with the seatbones.
For me a half halt is a rebalancing aid, firstly to take weight back and engage both hind legs. However you can also use a half halt to activate a particular hind leg to take more weight. You can use a quarter/in or shoulder/in half halt. If I am riding on the left rein and I feel the left hind needs to carry more I will give a slight shoulder/in half halt. If on the same left rein the right leg needs to carry more I can give a quarter/in half halt. These movements ask different legs to carry the weight,it need only be a feeling of the movement,you also need to be able to feel the hind legs of your horse to do this effectively. It helps to have someone on the ground if you are not sure about this,they can tell you when your horses inside leg is moving forwards,you can then remember the feeling through your seat at that moment,it takes time and practice but developing your feel of this will help when you come to give an aid.
This is a huge topic and there are many different kinds of half halt,you can also half halt with the inside rein,closing your fingers around the rein and releaseing to check the horse will search forward towards the hand. I have been working on asking my horse to take weight back, we have been experimenting with a half halt at liberty,with tack in hand and in riding. In riding we have extra breathing,seat,weight and rein aids so providing we understand how to use them it should be easier. I have found though that my half halt at liberty has really started to work,when I use tack I think maybe my focus changes and I concentrate too much on the rein aids,I want my horse to respond to these rein aids but I need to keep my intention and body language as clear as it is at liberty.
Here is a little video of us playing with some of these ideas. Its early days and still difficult so you have to really look for the shift in weight but things are starting to happen.